What we expect is not always what we get: evidence for both the direction-of-change and the specific-stimulus hypotheses of auditory attentional capture.

Nöstl A, Marsh JE, Sörqvist P - PLoS ONE (2014)

Bottom Line:
Experiment 1 found that deviants capture attention as a function of the pitch difference between the deviant and the replaced/expected tone.The results support the expectation violation account of auditory distraction and suggest that there are at least two different expectations that can be violated: One appears to be bound to a specific stimulus and the other would seem to be bound to a more global cross-stimulus rule such as the direction-of-change based on a sequence of preceding sound events.Factors like base-rate probability of tones within the sound environment might become the driving mechanism of attentional capture--rather than violated expectations--in complex sound environments.

Affiliation: Department of Building, Energy and Environmental Engineering, University of Gävle, Gävle, Sweden.

ABSTRACTParticipants were requested to respond to a sequence of visual targets while listening to a well-known lullaby. One of the notes in the lullaby was occasionally exchanged with a pattern deviant. Experiment 1 found that deviants capture attention as a function of the pitch difference between the deviant and the replaced/expected tone. However, when the pitch difference between the expected tone and the deviant tone is held constant, a violation to the direction-of-pitch change across tones can also capture attention (Experiment 2). Moreover, in more complex auditory environments, wherein it is difficult to build a coherent neural model of the sound environment from which expectations are formed, deviations can capture attention but it appears to matter less whether this is a violation from a specific stimulus or a violation of the current direction-of-change (Experiment 3). The results support the expectation violation account of auditory distraction and suggest that there are at least two different expectations that can be violated: One appears to be bound to a specific stimulus and the other would seem to be bound to a more global cross-stimulus rule such as the direction-of-change based on a sequence of preceding sound events. Factors like base-rate probability of tones within the sound environment might become the driving mechanism of attentional capture--rather than violated expectations--in complex sound environments.

pone-0111997-g002: An illustration of the design of Experiment 1 and the possible tone replacement at the sequence position wherein the tone E5 would be presented in the original ‘Twinkle, twinkle, little star’ sound sequence.The light grey circle indicates the replaced tone (E5) and the black circles depict replacing/deviant tones. The set of replacing/deviant tones included F#5 (i.e., a small deviation from the replaced tone and an unexpected sequence-change direction), F5 (i.e., a perceptual change from the previous sound stimulus is held constant, but a small deviation from the replaced tone and an unexpected change direction), E4 (i.e., an intermediate deviation from the replaced tone, but a change in the expected direction) and E3 (i.e., a large deviation from the replaced tone, but a change in the expected direction).

Mentions:
The musical notes used in Experiment 1 were ‘A, C, D, E, F, G’ (all played in octave band 5). As shown in Figure 2, the ‘E5’ note, which always follows immediately after an ‘F5’, was occasionally replaced by one of four pattern-deviants (‘E3’, ‘E4’, ‘F5’, ‘F#5’). According to the specific-stimulus hypothesis, the pitch difference between the exact expected tone and the pattern-deviant should be the basis of the magnitude of attentional capture. Hence, this account predicts that ‘E3’ will be the most captivating pattern-deviant as it differs the most from the expectation of ‘E5’. On the other hand, according to the direction-of-change hypothesis, ‘F#5’ should be the most captivating pattern-deviant, as the participants should expect a drop in pitch after ‘F5’ and the presentation of ‘F#5’ instead of ‘E5’ violates this expectation. Pattern-deviants ‘E3’ and ‘E4’, in contrast, should not capture attention as they both confirm the expectation of a drop in pitch. In addition, we included a control condition wherein the perceived local change from the preceding stimulus to the pattern-deviant was held constant (i.e., when the pattern-deviant is ‘F5’). Moreover, all pattern-deviants had equal base-rate probability to rule out the possibility that differences in rarity contribute to the differences between conditions.

pone-0111997-g002: An illustration of the design of Experiment 1 and the possible tone replacement at the sequence position wherein the tone E5 would be presented in the original ‘Twinkle, twinkle, little star’ sound sequence.The light grey circle indicates the replaced tone (E5) and the black circles depict replacing/deviant tones. The set of replacing/deviant tones included F#5 (i.e., a small deviation from the replaced tone and an unexpected sequence-change direction), F5 (i.e., a perceptual change from the previous sound stimulus is held constant, but a small deviation from the replaced tone and an unexpected change direction), E4 (i.e., an intermediate deviation from the replaced tone, but a change in the expected direction) and E3 (i.e., a large deviation from the replaced tone, but a change in the expected direction).

Mentions:
The musical notes used in Experiment 1 were ‘A, C, D, E, F, G’ (all played in octave band 5). As shown in Figure 2, the ‘E5’ note, which always follows immediately after an ‘F5’, was occasionally replaced by one of four pattern-deviants (‘E3’, ‘E4’, ‘F5’, ‘F#5’). According to the specific-stimulus hypothesis, the pitch difference between the exact expected tone and the pattern-deviant should be the basis of the magnitude of attentional capture. Hence, this account predicts that ‘E3’ will be the most captivating pattern-deviant as it differs the most from the expectation of ‘E5’. On the other hand, according to the direction-of-change hypothesis, ‘F#5’ should be the most captivating pattern-deviant, as the participants should expect a drop in pitch after ‘F5’ and the presentation of ‘F#5’ instead of ‘E5’ violates this expectation. Pattern-deviants ‘E3’ and ‘E4’, in contrast, should not capture attention as they both confirm the expectation of a drop in pitch. In addition, we included a control condition wherein the perceived local change from the preceding stimulus to the pattern-deviant was held constant (i.e., when the pattern-deviant is ‘F5’). Moreover, all pattern-deviants had equal base-rate probability to rule out the possibility that differences in rarity contribute to the differences between conditions.

Bottom Line:
Experiment 1 found that deviants capture attention as a function of the pitch difference between the deviant and the replaced/expected tone.The results support the expectation violation account of auditory distraction and suggest that there are at least two different expectations that can be violated: One appears to be bound to a specific stimulus and the other would seem to be bound to a more global cross-stimulus rule such as the direction-of-change based on a sequence of preceding sound events.Factors like base-rate probability of tones within the sound environment might become the driving mechanism of attentional capture--rather than violated expectations--in complex sound environments.

Affiliation:
Department of Building, Energy and Environmental Engineering, University of Gävle, Gävle, Sweden.

ABSTRACTParticipants were requested to respond to a sequence of visual targets while listening to a well-known lullaby. One of the notes in the lullaby was occasionally exchanged with a pattern deviant. Experiment 1 found that deviants capture attention as a function of the pitch difference between the deviant and the replaced/expected tone. However, when the pitch difference between the expected tone and the deviant tone is held constant, a violation to the direction-of-pitch change across tones can also capture attention (Experiment 2). Moreover, in more complex auditory environments, wherein it is difficult to build a coherent neural model of the sound environment from which expectations are formed, deviations can capture attention but it appears to matter less whether this is a violation from a specific stimulus or a violation of the current direction-of-change (Experiment 3). The results support the expectation violation account of auditory distraction and suggest that there are at least two different expectations that can be violated: One appears to be bound to a specific stimulus and the other would seem to be bound to a more global cross-stimulus rule such as the direction-of-change based on a sequence of preceding sound events. Factors like base-rate probability of tones within the sound environment might become the driving mechanism of attentional capture--rather than violated expectations--in complex sound environments.